The present invention is directed to a continuous process for forming burls in a solid surface material comprising a filled acrylic composition exhibiting a series of burls present on the surface of the material.
The formation of different surface appearances in a solid surface material such as used for countertops and sinks is well known in the prior art.
Iverson, U.S. Pat. No. 3,816,155, discloses a method for producing protective coatings in simulation of wood graining. The method comprises preparing a plurality of portions of thixotropic viscous settable resins colored with metallic pigments in different colors. These separate portions of vehicle are combined with a minimum of admixing, either in a common container from which the mixture is applied to a base surface, or by spreading the several vehicle portions onto a base. The applied coating mixture is allowed to level or is leveled into a relatively uniform layer. While liquid and viscous, the leveled coating is furrowed to develop a lined pattern therein in simulation of wood graining. The coating is permitted to set up and harden and may be formed on a non-adhering surface from which it is stripped as a self-sustaining film.
Iverson, U.S. Pat. No. 3,904,791 also discloses a method for producing protective coatings in simulation of wood graining, leather, and like effects such as sandblasted graining, distressed wood graining, burled graining, elephant hide leather may be obtained by variations of the basic method. The resin may be cast in slabs or blocks of substantial thickness from which veneer layers may be removed.
Murakami, et al., U.S. Pat. No. 4,710,333 provide teachings for a continuous process in formation of synthetic resin plates having an irregular flow pattern of different colors.
Stecker, U.S. Pat. No. 5,055,324 prepares synthetic surfaces having a pattern simulating stone, marble and other natural substances by combining a resin matrix with a veining pigment composition with a specific gravity heavier than the resin system. In addition, a blooming agent component is employed with a specific gravity less than the resin system.
Barnett, U.S. Pat. No. 6,011,101, discloses a process for making a marble casting material by partial intermingling of two or more partially incompatible marble casting resins that are not intended to be normally used in combination.
A need is present in solid surface materials for varying surface appearances which extend into the interior of such materials.
The present invention is directed to a continuous method of incorporating a burl appearance into solid surface material comprising the steps of:
a) forming two separate acrylic resin suspension streams with a first stream having
i) a viscosity in a range from 500 to 3,000 centipoise,
ii) a density in a range from 1.5 to 1.7 grams per milliliter and
iii) a surface tension in a range from 35 to 45 dyne per centimeter and
a second stream having
i) a viscosity in a range from 500 to 3,000 centipoise and
ii) a density in a range from 1.6 to 1.8 gram per milliliter with the proviso that the second stream has a density of at least 0.05 gram per milliliter more than the first stream and the second stream has a surface tension of at least 0.5 dyne per centimeter greater than the first stream and
b) continuously feeding one of the streams into a mixing chamber
c) continuously injecting one of the streams into the other stream within the mixing chamber wherein partial mixing takes place
d) flowing the partially mixed streams onto a support
e) curing the two suspensions whereby a series of three-dimensional burls are formed.